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Proud Mary

Sat Jan 25 2014, 08:30PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Mads Barnkob wrote ...

Proud Mary wrote ...

Mads Barnkob wrote ...

I moved the unit from a protective wooden box and it is now directly exposed to the weather in a water tight plastic pouch. The temperature dropped and so did the sensitivity of the tube, atleast the CPM fell about 1-2 cpm in average.

Why do you think that the sensitivity of the tube had dropped? One of the reasons that GM tubes have reamined popular despite their very basic character, is because they are quite insensitive to ambient changes.

Much more likely that your tube is detecting fewer particles because there a fewer particles to detect. Perhaps you should think of air temperature as being part of a weather process. It may be colder because the wind is blowing from a different direction, for example, so fewer radioactive airborne particulates are arriving at Haus Barnkop than happens when the wind is blowing from a contaminated area. The height of airborne particulate smogs will rise and fall with temperature and affect counting, as does the release of radon from rocks as cold weather splits them. Then there is the diurnal and semi-diurnal flux of solar cosmic rays which will certainly be very significant when you are talking about 1 - 2 cpm.

That was my first thought at the time as I moved it from the wooden enclosure to the post and its temperature dropped over 10 degrees, the counting dropped at the same instant. But the counting also went up again without temperature changing when I moved it further away.

I suspect it could be the lead plates used at the edges of the roof construction that shielded the detector.

Mads Barnkob wrote ...

Proud Mary wrote ...

Many of the gamma rays you are detecting will be coming from the bricks, concrete, cement, and roof tiles in your house, so the detector's proximity to the structure will have a significant effect on your total counts.

Also your balcony and your roof is likely to be collecting particulates falling from the sky. The rain gutter, if you have one, will concentrate radionuclides that have fallen as particles or in rain that has fallen on the roof, and could be a very interesting study in its own right - potentially more sensitive (because of greater effective capture area/aperture) than the detector located in the 'standard' position 1m above the ground.

radhoo

Sat Jan 25 2014, 08:37PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

Guys, I'll just post a small update then I'll check out your messages

Here are some news:

I was able to design and manufacture a new PCB, moving from a DIP microcontroller (as in previous models) to SMD. By doing so I save previous space, preparing for the Model B design, that will also feature a LCD to be used not only as a fixed monitoring station, but also as a portable dosimeter.

.
Some details here.

Finally, some progress on the web portal that shows the centralized data. For now just minor changes, but important ones:

The data is more user friendly and the meaningless numbers are gone. Now the online/offline status of a given station is available . We know this by checking the timestamp of the last data package received from the station. If older than 5 minutes , we consider it offline. Normally , the uRADMOnitor units send radiation measurements every minute.
The portal shows the latest readings: radiation + internal temperature (yes, there is also a temperature sensor inside). Then the bottom of the detailed view window shows the radiation history for the last 24 hours.
More details here.

The portal can be accessed at http://www.uradmonitor.com

radhoo

Sat Jan 25 2014, 09:10PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

wrote ...

how much do these SI-29BG tubes cost you each?
I am re-reading this entire thread, im willing to participate if the California pacific coast interests you.

The tubes getting in my hand are relatively expensive, as now every seller in Ukraine or Russia is aware of Ebay and the prices used there. I'll drop you a PM for a unit. Would be great to have a unit in California! Currently I have run out of cases, but I am expecting more in the next few days.

Shrad wrote ...

I'd also be willing to participate, but will need to consider things beforehands like tidying my mess etc...
if interested, I can help in plotting data variation on a map for a period of time, but a wider network would be needed over an area to achieve good interpolation

That would be great. Plotting over a larger area is impractical with this model, but model C will feature a GPS receiver combined with an SDCard to log radiation data precisely mapped to location. However the timeframe for developing it goes as far as the end of this year.

Conundrum wrote ...

Wonder why there is such a profound effect on the tube from temperature?
Sure it isn't some other part drifting such as the zeners?

Today I had to heat a unit to melt an insulating lacquer layer pulverized over the bottom of the PCB. The temperature went as high as 100 degrees celsius. Then I plugged it to the network: the temperature sensor was still showing >55 degrees celsius but the Geiger counter was counting the normal values!

Proud Mary wrote ...

Why do you think that the sensitivity of the tube had dropped? One of the reasons that GM tubes have reamined popular despite their very basic character, is because they are quite insensitive to ambient changes.

I agree. I was not expecting to see this today. But the pulses were well between the normal counting interval, despite the very high temperature of the tube, and the entire board.

Conundrum wrote ...

It might also be worth adding an E field monitor so that this can be compensated for and logged.
Re. Altitude, what about a kite? Low tech but useful and on a windy but gust free day a box kite would be a reliable way to do tests.

I'll do my best to add various sensors that can prove useful correlations to the radiation data, but for now I need to keep to the vital requirements if I am to succeed in ever finishing this project. Currently the plan is Model A (done) + Model B( almost there) + Model C and the server infrastructure (not easy). Regarding the kite, I need very reliable sensors to integrate them easy and convenient to the current design. I am considering the BMP85 sensor, it comes calibrated from the factory, has a reasonable price and very good performance, and... I've worked with it in the past, so I have the code ready.

Mads Barnkob wrote ...

I suspect it could be the lead plates used at the edges of the roof construction that shielded the detector.

Proud Mary wrote ...

Also your balcony and your roof is likely to be collecting particulates falling from the sky. The rain gutter, if you have one, will concentrate radionuclides that have fallen as particles or in rain that has fallen on the roof, and could be a very interesting study in its own right - potentially more sensitive (because of greater effective capture area/aperture) than the detector located in the 'standard' position 1m above the ground.

Mads, do you have pics of both the places ? Would love to have a look. Stella's assumption seems very reasonable.

Mads Barnkob

Sat Jan 25 2014, 09:47PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

At first it was inside the black table also in the first picture, there is a lead plate all along the grey edge behind the unit, it is a part of the edge of the roof construction. I would say that the distance to the rain gutter did not change that much.

The new location is at the edge of the balcony, adding the rubber duck did not affect readings ;) It only works as adding Wife-Acceptance-Factor to having measuring devices installed on the balcony.

tobias

Sat Feb 08 2014, 12:48AM

Registered Member #1956 Joined: Wed Feb 04 2009, 01:22PM
Location: Jersey City
Posts: 172

I am proud to see my city on the map =)
BTW, very nice work with the location detection Radu. It was seamless!

It will sit on the inside close to the window until the weather improves.

radhoo

Sat Feb 08 2014, 10:48AM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

Tobias, that last unit sure looks great on the map, especially considering the important location it is running at.

I finally found the perfect case for the Model A. It is a high quality aluminum case, that comes with a nice wall mount.

I have the option of adding a rubber gasket to one of the ends, opposite to the one with all the connectors, to make it water proof (if mounted with the connectors down).
I have only a few of these, so before I get a good supplier, I'll need to continue using the black ones.

radhoo

Sun Feb 16 2014, 10:09PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

The finished wall mount case variant:

More photos on here.

For sale:
For those interested in installing a radiation monitor to keep an eye on the readings at any given location (very much like the nodes on

) , I finally have a few extra Model A units that I can sell.

2 units currently available, more to be completed soon. PM me if interested! These are completely handmade, hope to have machine made (pcb+case) units soon, but they do come with charger, cables and the unit itself, encased in the nice rugged aluminium enclosure.

Shrad

Mon Feb 17 2014, 09:12AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

if you want to be able to plot data over a map, you have to have your data stored in a fully fledged database system (I guess this is the case already)

once you have a fully functional machine built unit, it would also be a nice thing to develop a dedicated website so you have full control over what is done

for data acquisition, if you have a TCP stack, I advise you to develop a web-service approach like SOAP or any format you can choose so that it complies with what is foreseen with the IoT (internet of things), like how to publish and consume data in this field of application

radhoo

Mon Feb 17 2014, 03:28PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

Hi Shrad, thanks for your feedback (also the one you've sent on PM) . Most of what you are saying here is already in place, see

. The website runs on a dedicated server, both maintaining a (large) database but also building charts. Later SMS / email notifications.

There a lot more work to be done. Thanks to the community support and my personal funding, I was able to get this far. If I find a way to get it on Kickstarter, we would probably see this happen sooner.

Shrad

Mon Feb 17 2014, 09:25PM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

did you get a look at kisskissbankbank? I guess there are other community fundings out there

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